hw/i386/pc_piix: Move i440fx' realize near its qdev_new()

I440FX realization is currently mixed with PIIX3 creation. Furthermore, it is
common practice to only set properties between a device's qdev_new() and
qdev_realize(). Clean up to resolve both issues.

Since I440FX spawns a PCI bus let's also move the pci_bus initialization there.

Note that when running `qemu-system-x86_64 -M pc -S` before and after this
patch, `info mtree` in the QEMU console doesn't show any differences except that
the ordering is different.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230630073720.21297-18-shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/pc_piix.c

@@ -114,7 +114,7 @@ static void pc_init1(MachineState *machine,
     X86MachineState *x86ms = X86_MACHINE(machine);
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *system_io = get_system_io();
-    PCIBus *pci_bus;
+    PCIBus *pci_bus = NULL;
     ISABus *isa_bus;
     int piix3_devfn = -1;
     qemu_irq smi_irq;
@@ -126,7 +126,6 @@ static void pc_init1(MachineState *machine,
     MemoryRegion *rom_memory = system_memory;
     ram_addr_t lowmem;
     uint64_t hole64_size = 0;
-    Object *phb = NULL;
 
     /*
      * Calculate ram split, for memory below and above 4G.  It's a bit
@@ -198,11 +197,36 @@ static void pc_init1(MachineState *machine,
     }
 
     if (pcmc->pci_enabled) {
+        Object *phb;
+
         pci_memory = g_new(MemoryRegion, 1);
         memory_region_init(pci_memory, NULL, "pci", UINT64_MAX);
         rom_memory = pci_memory;
+
         phb = OBJECT(qdev_new(host_type));
         object_property_add_child(OBJECT(machine), "i440fx", phb);
+        object_property_set_link(phb, PCI_HOST_PROP_RAM_MEM,
+                                 OBJECT(ram_memory), &error_fatal);
+        object_property_set_link(phb, PCI_HOST_PROP_PCI_MEM,
+                                 OBJECT(pci_memory), &error_fatal);
+        object_property_set_link(phb, PCI_HOST_PROP_SYSTEM_MEM,
+                                 OBJECT(system_memory), &error_fatal);
+        object_property_set_link(phb, PCI_HOST_PROP_IO_MEM,
+                                 OBJECT(system_io), &error_fatal);
+        object_property_set_uint(phb, PCI_HOST_BELOW_4G_MEM_SIZE,
+                                 x86ms->below_4g_mem_size, &error_fatal);
+        object_property_set_uint(phb, PCI_HOST_ABOVE_4G_MEM_SIZE,
+                                 x86ms->above_4g_mem_size, &error_fatal);
+        object_property_set_str(phb, I440FX_HOST_PROP_PCI_TYPE, pci_type,
+                                &error_fatal);
+        sysbus_realize_and_unref(SYS_BUS_DEVICE(phb), &error_fatal);
+
+        pci_bus = PCI_BUS(qdev_get_child_bus(DEVICE(phb), "pci.0"));
+        pci_bus_map_irqs(pci_bus,
+                         xen_enabled() ? xen_pci_slot_get_pirq
+                                       : pc_pci_slot_get_pirq);
+        pcms->bus = pci_bus;
+
         hole64_size = object_property_get_uint(phb,
                                                PCI_HOST_PROP_PCI_HOLE64_SIZE,
                                                &error_abort);
@@ -239,28 +263,6 @@ static void pc_init1(MachineState *machine,
         PIIX3State *piix3;
         PCIDevice *pci_dev;
 
-        object_property_set_link(phb, PCI_HOST_PROP_RAM_MEM,
-                                 OBJECT(ram_memory), &error_fatal);
-        object_property_set_link(phb, PCI_HOST_PROP_PCI_MEM,
-                                 OBJECT(pci_memory), &error_fatal);
-        object_property_set_link(phb, PCI_HOST_PROP_SYSTEM_MEM,
-                                 OBJECT(system_memory), &error_fatal);
-        object_property_set_link(phb, PCI_HOST_PROP_IO_MEM,
-                                 OBJECT(system_io), &error_fatal);
-        object_property_set_uint(phb, PCI_HOST_BELOW_4G_MEM_SIZE,
-                                 x86ms->below_4g_mem_size, &error_fatal);
-        object_property_set_uint(phb, PCI_HOST_ABOVE_4G_MEM_SIZE,
-                                 x86ms->above_4g_mem_size, &error_fatal);
-        object_property_set_str(phb, I440FX_HOST_PROP_PCI_TYPE,
-                                pci_type, &error_fatal);
-        sysbus_realize_and_unref(SYS_BUS_DEVICE(phb), &error_fatal);
-
-        pci_bus = PCI_BUS(qdev_get_child_bus(DEVICE(phb), "pci.0"));
-        pci_bus_map_irqs(pci_bus,
-                         xen_enabled() ? xen_pci_slot_get_pirq
-                                       : pc_pci_slot_get_pirq);
-        pcms->bus = pci_bus;
-
         pci_dev = pci_create_simple_multifunction(pci_bus, -1, true,
                                                   TYPE_PIIX3_DEVICE);
 
@@ -285,7 +287,6 @@ static void pc_init1(MachineState *machine,
         rtc_state = ISA_DEVICE(object_resolve_path_component(OBJECT(pci_dev),
                                                              "rtc"));
     } else {
-        pci_bus = NULL;
         isa_bus = isa_bus_new(NULL, system_memory, system_io,
                               &error_abort);